1. Field of the Invention
The present invention relates to a lighting apparatus for vehicles such as motor vehicles, and more specifically, to a vehicle lighting apparatus comprising lamp deflection angle controlling apparatus for controlling the changes in direction of beam of the lamp corresponding to the traveling conditions, for example, an adaptive front-lighting system (hereinafter referred to as AFS) for ensuring driving safety against a disorder occurred in the system.
2. Description of the Related Art
The AFS proposed for enhancing driving safety of motor vehicles detects information on the steering angle of the steering wheel SW of the motor vehicles, the vehicle speed, and other traveling conditions of the motor vehicles by the sensor 1, and the detected output is input to the electronic control unit 2 (hereinafter referred to as ECU) as shown in FIG. 1. The ECU 2 controls the swivel type lights 3R, 3L provided respectively on the left and right of the front portion of the motor vehicle, that is, the headlamps 3 that the direction of radiation can be deflected in the lateral direction based on the supplied sensor outputs. Such a headlamp may include, as a structure that can turn the reflector provided in the headlamp in the horizontal direction, a structure that can turn the reflector by the driving source such as a motor or the like. A mechanism for this turning is referred to as an actuator in this specification. According to the AFS in this type, when the motor vehicle travels on the curved road, the portion of the road ahead of the curve may be illuminated corresponding to the traveling speed of the motor vehicle, thereby effective in improving driving safety.
However, when a failure occurred in the AFS, especially when it became uncontrollable in a state in which the direction of radiation of the headlamp is deflected either to the left or the right with respect to the straight ahead direction of the motor vehicle, the forward of the motor vehicle cannot be illuminated when motor vehicle is driving straight ahead or turning along the curve in the opposite direction, or it may be fixed in the state of being deflected toward oncoming cars, which may dazzle the oncoming cars and thus deteriorate driving safety. Failures in the AFS includes, in the AFS shown in FIG. 1 for example, a case where the sensor 1 is broken down and thus the sensor outputs is not supplied from the sensor 1 to the ECU 2, a case where the ECU 2 is broken down, and a case where the actuator in the headlamp 3 is broken down, and in any cases, the AFS cannot function normally. Therefore, the AFS is required to have a capability that prevents deteriorating of safety even when a failure occurred, that is, failsafe capability.
The object of the present invention is to provide a vehicle lighting apparatus having failsafe capability ensuring driving safety even when a disorder occurred in the AFS.
According to the present invention, there is provided a vehicle lighting apparatus including lamp deflection angle controlling means for controlling the deflection angle of the lamp in the horizontal direction corresponding to the traveling conditions of the vehicle. The vehicle lighting apparatus comprises abnormality detecting means for detecting abnormality in the lamp deflection angle controlling means, and means for adjusting optical axis of the lamp in the vertical direction for setting the vertical angle of the optical axis of the lamp to the angular position lower than the reference angle upon receipt of abnormality-detected signal from the abnormality detecting means. The means for adjusting optical axis of the lamp in the vertical direction comprises for example a leveling mechanism for tilting the lamp in the vertically upward and downward directions, and adapted to tilt the optical axis of the lamp downward upon receipt of the system abnormality detected signal Preferably, the lamp deflection angle controlling means is adapted to be capable of controlling the deflection angles of a plurality of lamps provided in the vehicle, and the means for adjusting the optical axis of the lamp in the vertical direction is adapted to tilt the optical axes of the lamps other than those in abnormal condition downward and also in the lateral direction so that the lamp irradiates the front.
According to the present invention, when the AFS that constitutes the lamp deflection angle controlling means lapsed into malfunction, the optical axis of the lamp that is in the deflected state is tilted vertically downward, whereby the lamp is prevented from dazzling oncoming cars even when it is in the state of being deflected toward the oncoming cars, thereby realizing failsafe capability which is favorable in terms of traffic safety. In addition, by utilizing pulse signals supplied from the hall elements attached on the motor when controlling the revolution of the motor, additional components aside from the existing motor are not necessary, thereby preventing increase in complexity of construction and in the cost.